Estrogens in Scleractinian Corals: Sources, Metabolism, and Physiological ActivityEPA Grant Number: U915750
Title: Estrogens in Scleractinian Corals: Sources, Metabolism, and Physiological Activity
Investigators: Tarrant, Ann M.
Institution: University of Hawaii at Manoa
EPA Project Officer: Michaud, Jayne
Project Period: December 1, 2000 through December 1, 2003
Project Amount: $91,048
RFA: STAR Graduate Fellowships (2000) RFA Text | Recipients Lists
Research Category: Fellowship - Oceanography , Aquatic Ecosystems , Academic Fellowships
The objective of this research project is to determine what role, if any, estrogens play in coral reproduction, and how external estrogens affect corals. This study will: (1) determine the uptake kinetics of estrogens from the water column by corals; (2) investigate pathways for estrogen synthesis and metabolism; (3) test the effects of exogenous estradiol on coral gametogenesis and tissue growth and composition; and (4) identify nuclear receptor(s) in coral tissue.
To describe the uptake of dissolved estrogens by corals, experiments will be conducted in a 24-m flume filled with 2 m2 of scleractinian corals. The flume will be spiked with estrone (1-2.5 ng/l); water samples that have been collected over 1-7 days will be analyzed by immunoassay. Metabolic pathways will be investigated by adding deuterated testosterone and estradiol to coral homogenates. Resulting metabolites will be identified by gas chromatography/mass spectrometry (GC-MS). Effects of estrogens on reproduction will be tested by dosing Montipora verrucosa colonies with estradiol prior to spawning and quantifying fecundity over the reproductive season. Additional experiments will test the effects of estrogens and other steroids on coral skeletal growth and tissue thickness and composition. Degenerate primers also will be used to identify an "orphan" receptor (a form of COUP-TF) in two coral species. In situ hybridization will be used to describe COUP-TF expression in coral tissues.
Investigation of uptake kinetics and metabolic pathways will elucidate estrogen cycling in corals. Testing effects of exogenous estrogens on coral tissues will provide some understanding of the effects (if any) of estrogens on reef-building corals. In vertebrates, estrogens act through specific high-affinity receptors to activate genes, but estrogen action in invertebrates is poorly understood.